SLC39A7 and breast cancer: Taylor and coworkers have proposed that phosphorylation of ZIP7 might induce release of Zn2+ from the ER to the cytosol in Tamoxifen-resistant MCF-7 breast cancer cells (TamR).22 Using the membrane-permeable Zn2+-specific indicator Newport Green DCF a 2-fold higher fluorescence was observed in TamR cells compared to wild-type MCF-7 cells, suggesting a higher intracellular free Zn2+ concentration.22 Comparison of the expression levels of several Zn2+ importers (ZIPs) revealed a significant increase in expression level of ZIP7 in TamR cells compared to wild-type MCF-7 cells.